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The designers of the new Canada Science and Technology Museum knew that one job stood out: this time, they had to keep out the rain and snow.
Years of chronic roof leaks doomed the old museum as water and mould crept through the building.
The crumbling roof dropped bits of asbestos on visitors and staff. It dripped water onto artifacts. An evaluation in 2014 warned that a winter with 25 centimetres of snow could even make the roof cave in.
Patch after patch failed to fix it until finally engineers tested the mould levels and ordered everyone out in a hurry in late 2014.
They replaced the museum. And for another $156.4 million, designers planned a giant Collections and Conservation Centre next door to it to hold the majority of the museum collection, artifacts too numerous to exhibit in the main building.
But once again they hit a roof problem. It forced them to scrap their original design that “wrapped around” the main museum building, and they substituted a smaller and less efficient structure for the same price.
The reason: The wraparound design made snow on the roof a harder problem to solve.
Snow had bedevilled the old museum roof, and now a report obtained from Treasury Board tells the sequel. One reason why the big Collections building’s initial design was abandoned, it says, was this: “The impact of winter conditions on a wraparound concept, in terms of snow loads on the roof, was underestimated.”
At Queen’s University, Mark Green is the assistant head of civil engineering. He explains that while engineers are good at making a roof that will stand up to snow, not all snow loads are the same.
Buildings out in open spaces get more wind, for instance, and this blows snow off the roof. If a building is sheltered, snow will build up more and this requires more support.
Where two buildings adjoin, he says, snow drifts are going to form on the lower roof, piling up against the shelter of the taller building’s wall. This adds weight on the lower roof.
“If it were wrapped around like that, you basically get a triangular pile of snow against the other building. And so that would be a significantly higher snow load than if you have just a square building in a separate location,” he said.
This phenomenon of an extra-deep snowdrift load is described in work from the National Research Council, Green noted. The NRC has been a leader in research into snow loads on roofs dating back for decades.
But recognizing the extra load came too late for the museum. Construction of the main building was already well under way, and it was too late to change that building’s roof design to handle the extra load caused by the proposed Collections building.
The solution was to build the new structure away from the main museum building, and this redesigned Collections building is smaller than the one originally planned.
Treasury Board now says that the Collections building, which is scheduled to open next year, will not meet the museum’s long-term storage needs as its collection grows, or provide enough storage for the National Gallery of Canada, which wants to share the space.
“It is expected that the NMST may start running out of space in 2024,” Treasury Board reports. (It uses the formal name for the museum — National Museum of Science and Technology.)
The museum sent a brief email Tuesday saying that for now the building can hold its entire collection. It adds that there is “expansion potential” for the new Collections building, though it offered no details on when this might happen or what it would cost.
tspears@postmedia.com
twitter.com/TomSpears1
Timeline:
September 2014: Discovery of high mould levels causes management to close the museum indefinitely
November 2014: Announcement of $80.5 million to demolish and rebuild the museum.
April, 2016 Museum receives $156.4 million under Federal Infrastructure Initiative for a new Collections and Conservation Centre.
November 2017: Main museum re-opens.
March 2019: Expected date for opening of Collections building.
Collections centre — by the numbers
30% – How much smaller the building will be than planned.
$156.4 million – The cost.
4 – number of floors
$71.5 million – The increase in the estimates for electrical, mechanical and lab installations. The predicted cost went from $47.5 million to $119 million.
5 – Years before the building starts to run out of space.
查看原文...
Years of chronic roof leaks doomed the old museum as water and mould crept through the building.
The crumbling roof dropped bits of asbestos on visitors and staff. It dripped water onto artifacts. An evaluation in 2014 warned that a winter with 25 centimetres of snow could even make the roof cave in.
Patch after patch failed to fix it until finally engineers tested the mould levels and ordered everyone out in a hurry in late 2014.
They replaced the museum. And for another $156.4 million, designers planned a giant Collections and Conservation Centre next door to it to hold the majority of the museum collection, artifacts too numerous to exhibit in the main building.
But once again they hit a roof problem. It forced them to scrap their original design that “wrapped around” the main museum building, and they substituted a smaller and less efficient structure for the same price.
The reason: The wraparound design made snow on the roof a harder problem to solve.
Snow had bedevilled the old museum roof, and now a report obtained from Treasury Board tells the sequel. One reason why the big Collections building’s initial design was abandoned, it says, was this: “The impact of winter conditions on a wraparound concept, in terms of snow loads on the roof, was underestimated.”
At Queen’s University, Mark Green is the assistant head of civil engineering. He explains that while engineers are good at making a roof that will stand up to snow, not all snow loads are the same.
Buildings out in open spaces get more wind, for instance, and this blows snow off the roof. If a building is sheltered, snow will build up more and this requires more support.
Where two buildings adjoin, he says, snow drifts are going to form on the lower roof, piling up against the shelter of the taller building’s wall. This adds weight on the lower roof.
“If it were wrapped around like that, you basically get a triangular pile of snow against the other building. And so that would be a significantly higher snow load than if you have just a square building in a separate location,” he said.
This phenomenon of an extra-deep snowdrift load is described in work from the National Research Council, Green noted. The NRC has been a leader in research into snow loads on roofs dating back for decades.
But recognizing the extra load came too late for the museum. Construction of the main building was already well under way, and it was too late to change that building’s roof design to handle the extra load caused by the proposed Collections building.
The solution was to build the new structure away from the main museum building, and this redesigned Collections building is smaller than the one originally planned.
Treasury Board now says that the Collections building, which is scheduled to open next year, will not meet the museum’s long-term storage needs as its collection grows, or provide enough storage for the National Gallery of Canada, which wants to share the space.
“It is expected that the NMST may start running out of space in 2024,” Treasury Board reports. (It uses the formal name for the museum — National Museum of Science and Technology.)
The museum sent a brief email Tuesday saying that for now the building can hold its entire collection. It adds that there is “expansion potential” for the new Collections building, though it offered no details on when this might happen or what it would cost.
tspears@postmedia.com
twitter.com/TomSpears1
Timeline:
September 2014: Discovery of high mould levels causes management to close the museum indefinitely
November 2014: Announcement of $80.5 million to demolish and rebuild the museum.
April, 2016 Museum receives $156.4 million under Federal Infrastructure Initiative for a new Collections and Conservation Centre.
November 2017: Main museum re-opens.
March 2019: Expected date for opening of Collections building.
Collections centre — by the numbers
30% – How much smaller the building will be than planned.
$156.4 million – The cost.
4 – number of floors
$71.5 million – The increase in the estimates for electrical, mechanical and lab installations. The predicted cost went from $47.5 million to $119 million.
5 – Years before the building starts to run out of space.
查看原文...
